Control mechanism for refrigerating systems



May 21, 1946. R. e. THOMAS OONTRGL MECHANISM FOR REFRIGERATING SYSTEMS Filed June 16, 1941 3 Sheets-Sheet 1 R. M w 5 w m m G W m M .w

May 2l, 1946. R. G. THOMAS CONTROL MECHANISM FOR REFRIGERATING SYSTEMS Filed June 16, 1941 3 Sheets-Sheet 2 INVENTOR.

' RA Y 6.7'HOM/l5 BY HH II May 21, 1946. R. G. THOMAS CONTROL MECHANISM FOR REFRIGERATING SYSTEMS 3 Sheds-Sheet 3 Filed June 16, 1941 mmvmx.

19/? Y a. THOM/IJ B 4fl ATTOENEYJ Patented May 21,1946 7 UNITED STATES PATE comor. MECHANISM FOR nsr'm osna'r mo SYSTEMS A Ray G. Thomas, Bioomington, 111., assignor, by

- mesne cuts, to Eureka Williams'C0rD0- ratiorua corporationof Michigan Application June 1.6, 1941, Serial No. 398,l9 8

11 Claims. (cits-'4) This invention relates to refrigerating systems, with particular reference to refrigerators includ- Fig. 3 isan elevation of the embodiment shown in Fig. 2 taken from the left-hand side thereof ing a radiator and a compressor formingta part of a refrigerant circulating system. The invention is especially adapted foruse in connection with systems provided with a gas engine for operating the compressor.

It is an object of the invention to provide means operable by the pressure or temperature in the circulating system to control the operation of thegas engine. When a predetermined with the parts in low speed position.

Fig. l is a side elevation similar to that shown in Fig. 2, but illustratesan embodiment adapted for gradual control of the throttle from high low pressure obtains in the low pressure side of the circulating system, it is desirable to throttle the engine so that it will operate at idling speed. At a predetermined high pressure in the low pressure side, it. is desirable that the throttle should be opened so that the engine may operate at a predetermined high speed to reduce the ,-pressure in the low pressure side of the system.-

It is therefore an object of the present invention to provide a throttle control for the combustion'engine of a refrigerating'system wherein the control is operated by fluctuations in the pressure or temperature conditions in the system So that the engine speed may be varied in accordance with "refrigerating requirements.

A further object is to provide a throttle control of the character described in which the throttle is automatically operated with a snap action from Further objects will be apparent from the sp'ecification and the appended'claims.

In the drawings:

pressure of the Fig. 1 is a side elevation of one embodiment of the invention and illustrates the control inecha nism'as applied to a refrigerating'system including acompressor and a gas engine for operating the compressor. I

Fig. 2 is a side elevation of the throttle con-.

trol mechanism as applied to the gasengine of V the embodiment shown in Fig. 1.

speed position to idling speed position and vice versa.

i Fig. 5 is a somewhat diagrammatic view illustrating an embodiment wherein the pressure operated engine control co-operates with the ignition system to control the gas. engine.

Fig. 6 illustrates still another embodiment of the pressure control as applied to the ignition.

system.

Fig. 7 illustrates is preferably of the four cycle air-cooled type and is arranged to drive the, compressor by means of a belt 5 on suitable pulleys. The high pressure side of the compressorjis connected to the system by means of a high pressure conduit 6, and a low pressure conduit 1 connected to the crankcase of the compressor completes the circulation system in the usual manner. In accordance with this invention, controls areprovided for operating the gas engine and compressor so that, when the refrigerating coilis at a predetermined low temperature, the gas engine and com pressor will operate at idling speed,' and', when the pressure or temperature in the refrigeration coil rises. to a predetermined degree, the engine and compressor will operateat a predetermined, high speed to thereby reduce thepressure in the low pressure side of the refrigerating system.

The present invention provides a control de-- vice for the gas engine to accomplish the desired result, and in the embodiments shown inFigs. 1 to 4, inclusive, the device is controlled by varia-; tions in the low pressure side of the system The control may be accomplished either by a snap ac tion of .the throttle from idling speed position; to high speed position, and'v'ice .versa, in accordance with the requirements of the system as illustrated inf Fig. 2,. or the throttle may move gradually from idling speed position tohigh speed position, and vice versa, in. response to correanother embodiment of this invention wherein the control is effected by a 4 temperature responsive mechanism associated with the cooling coil of the refrigerating system.-

The embodiment as illustrated in Fig. 1 comprises aframe i on which is supported the usual refrigerant circulating system including a condenser 2, a compressor 3 which may be of the, I

usual piston type, and a gas engine 4; which latter sponding variations in pressure in the system, as shown in Fig. 4.

It is also contemplated to provide a control from the high pressure side of the compressor which control is adapted-to stop the engine completely when the desired refrigerating pressures have been obtained in the system. Furthermore, means is provided so that a suitable signal may be operated'whenever the engine is stopped.

In the embodiment shown in Figs. 1 and 2, a-

pressure operated device 8 is connected to the low pressure side of the'compressor 3 by means of the conduit I. This device is illustrated in detail in Fig. 2 and comprises a casing 9 mounted on a, bracket l and having a bellows ll mounted in. the casing to provide a. pressure chamber l2 connected to the low pressure side.

conduit I to move to partly closed position to cause the engine to operate at idling speed.

The lever 2| is provided with'an outwardly,

and upwardly extending-arm 26 provided with notches 21 adapted to receive the end of a. spring 28, the other end of which is adjustably secured to the frame of the engine by means of a threaded bolt 29 and athumb nut 30. The notches 2'! and the adjustable bolt and thumb nut provide means for accurately adjusting the tension of the spring 28,-which latter normally;

, will operate at idling speed until the pressure again rises to a predetermined degree in the conduit 1.

' As shown in Fig. 2, an adjusting screw 3| is provided in the bracket extension for limiting the downward movement of the toggle arm 18 so that a predetermined speed of the engine may determined pressures in the crankcase oi the I compressor.

A stem I5 is secured to the closed end of the bellows l I and extends through the bushing l4 and is slidably mounted therein. The lower end of the stem I5 is preferably guided in a depending portion 16 of the bracket Ill and is slotted to enable an arm I! to extend therethrough. The arm l1 and an opposed arm 18 are pivoted on the bracket at'IS and their free ends are connected by means of springs 20, as shown in Fig.

3. The arms l1. and I8 and associated springs 20 form a toggle mechanism which is shown in its normal high speed position. That is, the toggle is in the position which it normally occuples when the throttle is open so that the engine is operating at a predetermined high speed corresponding in response to a predetermined high pressure in the low pressure side of the system.

It will be obvious that, as the pressure is reduced in the conduit 1, which latter is connected to the low pressure side, preferably'to the crankcase of the compressor, the spring l3 will expand the bellows ll accordingly and, when the p essure is reduced a predetermined amount so that the arm I! and the corresponding ends of be maintained during the high speed portion of the cycle. A similar adjustable stop screw 3la may be provided above the arm l8 in order to accurately predetermine the low speed during I the idling portion of the cycle.

Fig. 4 illustrates another embodiment wherein the butterfly valve 24 is gradually moved from high speed position to idling speed, and vice versa, in response to variationsin pressure in the conduit 1. In this embodiment, a lever arm 32 extends through a slot in'the stem l5 and is pivoted at 33 on the bracket Illa. The opposite end ofthe lever 32 is slotted at 34 and engages over a pin 35 on the end of the lever Zia. This lever 2la is similar in all respects, except for the pin 35, to the lever 2| previously described. An adjustable stop screw 36, similar to the screw 3| of Fig. 2, is supported on the bracket Illa to limit the. position of the lever 32 to a predeter mined high speed position, and an adjustable stop screw 31, similar to thescrew 3| a of Fig. 2,

' ,is positioned on the bracket to limit the upper or the springs 20 pass the pivot point of the arms, V

the toggle mechanism will snap to the position shown in dotted lines whereupon the engine will operate at idling speed. Also, when the pressure increases in the'conduit I to a predetermined amount. the toggle mechanism will snap back to its original high pressure or corresponding high' speed position, as shown in, full lines.

In order to take advantage of this snap action responding to a predetermined high speed of the engine, and consequently the engine will operate at this high speed until the butterfly valve 24 is caused by the snap action of the toggle mechanism in response to lowered pressure in the idling speed position dotted lines.

It will be apparent that, when a predetermined high pressure obtains in the conduit 1, the throttle operating mechanism will be in the posiof the lever as shown by tion illustrated in i'ull lines; whereby the throttle is positioned to operate the engine and associated compressor at a predetermined high speed and, as the pressure gradually reduces in the conduit 1, the throttle control mechanism will gradually move to the dotted line or low speed position, and

the gradual movement of the throttle in repressor by means of a conduit 38. In this embodiment the bellows device is preferably posi-' tioned adjacent a, spark plug 39 on the engine. A sna action mechanism substantially identical with that previously described is supported on a bracket lob preferably in the inverted position shown and the toggle arms "a and [8c are pivoted at 22a and the ends of the arms are connected by means of a spring 200. The arm la is provided with an upwardly extending rod 40 secured thereto and the entire toggle mechadotted lines.

' may be applied to the DGIIOWSIdGVlOQI previously described and illustrated in-.Figs.:.:1gtone. or the -bellows devices 8a and lb previouslyfdescribed I andiillustrated in Figs. .5 and 6,'inwhich;latt'er a groundedspring 4| and moves-the spring into sthe, ignition system may be :afiectedto control 1 the gasengine in accordance with refrigerating i nism is; movable by thebellows device rromthe full line, position which 1 corresponds .to high speed of the'compressorto the dotted line posi-' tion, in which latter. position the arm engages contact with the 'sparkpiug 88 as illustrated in In this dotted line position the sparkplug is shortedto theengine frame, thereby short-clrcuiting the ignition system-and stopping the engine. i ,-1 v 1.

-In this embodiment, after the engine stops,the pressure will graduallybe reducedinthe con;

duit 38, and. when a predetermined reduced" spark plug, and enabling the 5 engine to again be started by an operator. In order -to:signal the device of any suitabie'type. Such for instance as a 3 bell 42, may be providedin a normally. open-electric circuit 43.; When thevspark plug is shorted, @the spring contactmember 4| -will'close the circult 43, as illustratedby-dotted-lines and will which a bellows device'lb, which may be similar in-all respects to the bellows devices previously is connected to the high pressure :side of the compressor by means of a conduit 38a in the same manner as shown in 1 Fig. 5, the terminals requirements. 1. It, isintended, 'oI .course,-:that.-the invention '.,should not be limited to the specific embodiment I; or-embodiments'disclosed herein, since modiflcay-tions may be: made, audit is contemplated; therefore; by the appended claims. to cover any such v,;;.v.;modiflcations, as fall'within the true -spirit':and I pressure is. reached; the toggle mechanismawill automatically snap back to the original full line" 5 position.1-there by breaking the short. from the scopefoixthis invention. 4

Having. .thus' described this invention-,fwhat is claimed: and 1 desired to secured by Letters "ihzPatent'is: 1

' s "1. ,m a, refrigeratorsystem 'comprisinga comoperator when the engine istoppedqa signal Qepressorirathrottle ior said. engine, said throttle ."normallyspring tensioned toward high r iressor, -a gas enginexfor. operating said compeedlposition, snap-actingmeans controlled by I "fthe pressure in said system to move said throttle from high speed position to low speed "position energize the signal. 5 r 'Fig. 6 illustratesstill another embodiment in and vice vera in response to predetermined vari- .ations in: pressure in said system, and meanszto vary the resistance of said throttle to movement ,-.by said pressure controlled means.

2. In arefrigeratorsystemrcomprising.acom- 3 pressor,-a gas-engine for operating said compressor, aspeed'control device for :said' engine, a spring-tensionedz"over-centertoggle mechanism movable from one position to another {to move said speed control device with a snap action from high speed position :to low speed position of said engine, and vice. versa,'aflrst spring'm'eans normally tensioning said speed control 'device and said toggle mechanism toward 'said- 'high -speed '45 and 46 will ,be closed until a predetermined jpositionof said enginerand pressure-controlled high pressure is obtained in the conduitdfla. When the. pressure reaches .a' predetermined amount, the terminals and 46 will openand -therebystop the engine and-associated com-"Z pressor. These terminals will remain open until the pressure in the conduit 38a is again reduced to apredetermined amount, at which time the terminals and '48'will again close, andth'e engine may" then be started to begin a new cycle. A signal may be controlled by the terminal in the same manner as the signal is controlled ("in the embodiment illustrated in Fig. 5;

t Fig. 7 illustrates a slightly diil'erent embodiment in which the'pressure controldevice 8 for. operating the throttle is controlled by means of a temperature responsive element thermally associated with the cooling coil of the retrigeratingi system. In this embodiment a temperature responsive element 48 comprising a hollow bulb or the like is secured in heat conducting relation-1 0 Ship to a conduit 48 of the refrigerating system;

v The bulb '48 is preferably secured to'the sc -called suction line of the cooling coil of the refrigerating system and is charged with any suitable well known gas or liquid which re'adily expands and.

contracts in response to temperature changes. The bulb is connected to a bellows within the control device 8 by means or a conduit I0. In this embodiment the control elements are responcooling coil to thereby control the throttle oi the gas engine in substantially the same manner as the pressure controls previously described. It

will be understood, 0! course. that the tempera- .ture responsive embodiment illustrated in Fig.1 ll

means controlled by variationsfin'pressure ob- .taining in said system'and operableag'ai'nst the pressure of said spring-tensioned toggle mechanism to operate said speed control device. -3. A reirigeratorcomprisin'g the usual refrig- ;erant-circulating-system including a compressor,

" a gas engine forcontinuously operating said compressor,. a throttle for controlling the speed of said engine, said system having jahigh pressure side and a low pressure side, a pressure actuated control 'mechanim which responds to the pressures obtaining in oneof said pressure sides of the system, and a spring-tensioned over-center toggle mechanism disposed between said pressure actuated control mechanism and said throttle for snapping the throttle from high speed position to low speed position, and vice versa, when i the pressures in said pressure side or" the. system reach predetermined limits 4. In-a refrigerator system comprising a com- "sive topredetermin'ed temperature changes in the ing said speed control device in one speed position and in. said other position retaining said speed control device in another speedposition, andmeanscontrolled by variations of pressure in said system to move said toggle mechanism to overcome the resistance thereor by change in pressure in said system so that said toggle mecha nism and said speed control device will move to said high speed position and to said low speed position, and vice versa, with a snap action in response to a predetermined high pressure and a predetermined low pressure obtaining in said systems. v

5. In a refrigerator system comprising a compressor, a gas engine for operating said compressor, a speed control device for said engine for controlling two of its speeds,- means normally biasing said speed control device toward one of said speed control positions, a spring-tensioned said engine, said throttle being normally biased toward a position to control one speed of said engine, snap-acting means controlled by the pressures obtaining in said system by reason of the operationof said compressor to move said throttle with a snap action from said'flrst position to a second position to control another speed of said engine, and vice versa, in response to predetermined pressures obtaining in said system.

9. In a refrigerator system comprising a compressor, a prime mover for operating said compressor, a speed control device for said prime mover, said device in openposition controlling the high speed of said prime mover and in an-' other position controlling a lower speed ofsaid prime mover, spring means normally tensioriing said speed control device toward one ofxits said speed control positions, an cver-centersnap-acting toggle mechanism for actuating said speed trol device will move to both of said speed control positions with a snap action in response to predetermined pressures obtaining in said syst r 6 In a refrigerator system comprising a compressor, a gas engine for operating said compressor, a throttle for controlling the speed of said engine, said throttle being normally biased toward a position to control one speed of said engine, snap-acting means controlled by the pressure obtaining in said system by reason ofthe operation of said compressor to move said throttle with a snap action from said first position to a second position to control another speed of said engine, and vice versa, in response to predetermined variations in pressure obtaining in saidsystem, and means to vary the resistance of said throttle to movement by said snap -acting means from the said position toward which said throttle is normally biased,

7. In a refrigerator system comprising a compressor, a gas engine for operating said compressor, a throttle for controlling the speed of said engine, said throttle being normally biased toward a position to control one speed of said engine, and snap-acting means controlled by-the pressure obtaining in said system by reason of the operation of said compressor to move said throttle with a snap action from said first position to a' second position to control another speed of said engine, and vice versa, in response to predetermined variations in system. V s

8. In a refrigerator system comprising a compressor, a gas engine for operating said compressure obtaining said pressor, athrottle for controlling the speed of control device with snap. action from one of said speed control positions to the other cfsaid speed 10. In a refrigerator system comprising a com pressor, a prime mover for operating said compressor, a speed control device for said prime mover, said device inone position controlling the high speed of said prime mover and in another position controlling a lower speed oi. said prime mover, meansnormally biasing said speed control device toward one of its saidspeed control positions, snap-acting means for actuating said control device with a snap action from one of said speed control positions to the other of said speed V control positions, and vice versa, and means controlled by the pressures obtaining in said refrigerator system for actuating said snap-acting means.

11. In a refrigerator system comprising a compressor, a prime mover for operating said compressor, a speed control device for said prime mover, which device in one position controls the high speed of the said prime mover and in another position controls a lower speed thereof, said speed control device being normally biased to one of said speed control positions, snap-acting means controlled by the pressure obtaining in said system to move said speed control device with a snap action from one speed position to the other speed position, and vice versa, in response to predetermined variations in pressure obtaining in said system, and'means to vary the resistance of said speed control device to movement in at least one of said speed control positions by said snapacting means. v

RAY Gt THOMAS. 

